A known time indicator assembly 1 including migrating ink 2, such as shown in FIG. 1, produces a visible image after a period of time. The migrating ink 2 is applied to a base material 3, such as by printing, to form a back part 4 of the assembly 1. The back part 4 is adhesively joined with a front part 5 formed from one or more layers 7, 8, 9 of opaque and/or transparent material or coatings by an adhesive 6 to form and activate the assembly 1. Over a period of time, the migrating ink 2 of the activated assembly 1 migrates through the adhesive 6 to form a viewable image. The front part 5 and the back part 4 are not joined together until activation of the time indicator assembly 1 is desired. As a result, properly aligning the front part 5 and back part 4 to form and activate the assembly can be difficult.
This problem is solved by a time indicator assembly having a front part and a back part adhesively joined at one edge, such as disclosed in U.S. Pat. Nos. 5,107,470 and 5,974,003 which are fully incorporated herein by reference. These patents disclose an assembly having a front part and a back part similar to the time indicator assembly shown in FIG. 1. The back part includes migrating ink applied to a base material, and the front part includes one or more opaque coatings or layers. In order to ensure the front part and the back part are properly aligned, an edge of the front part is adhesively joined to the back part adjacent to the migrating ink. Prior to activation, a release liner interposed between the migrating ink and the front part prevents the migrating ink from contacting the front part and migrating through the opaque layers. When a user wishes to activate the assembly and initiate migration of the ink, the release liner is removed and the portion of the front part overlying the migrating ink is joined to the back part.
Since only one edge of the front part is joined to the back part, the front part is free to flop around. The floppy front part causes havoc when printing on outer surfaces of the assembly. Moreover, in one embodiment disclosed in the '470 patent, the release liner is folded over to form a pull tab for removing the release liner and activating the assembly. Prior to activation of the assembly, this folded release liner forms an assembly having an uneven thickness which causes further problems when attempting to print on an outer surface of the assembly.